1. Field of the Invention
This invention relates to fuel injection pump control system in diesel engines, and more particularly to a fuel injection pump control system in a diesel engine, most suitable for electronically controlling a fuel injection pump in a diesel engine.
2. Description of the Prior Art
In a conventional fuel injection pump used in a diesel engine the spill position for controlling fuel flow rate by a plunger is directly, mechanically controlled. If the spill position is directly controlled, the torque of the engine has substantially flat characteristics against a rotational speed as shown in FIG. 1. In a vehicle having mounted thereon such an engine as described above, rise of the torque of the engine is bad and the driving feeling is worse than in the gasoline motor vehicle.
In another known fuel injection pump movement of the accelerator pedal of a motor vehicle is imparted through a governor to operate the spill position. The torque characteristics of the fuel injection pump having the above-described construction are shown in FIG. 2. The torque characteristics against the rotational speed are very steep, and hence, a high torque can be obtained by a slight depression of the accelerator pedal. However, there is a possibility of occurrence of an abrupt start, so that it cannot be said that the above-described characteristics should necessarily be suitable for use in an engine to be mounted on a passenger vehicle.
Particularly, it is desired that the torque characteristics in a diesel engine are as close as possible to those in a gasoline engine.